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262 lines
6.0 KiB
C++
262 lines
6.0 KiB
C++
/*
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* DueWire.cpp - TWI/I2C library Arduino Due
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* Copyright (c) 2011 Cristian Maglie. All right reserved.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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extern "C" {
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#include <string.h>
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#include <inttypes.h>
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#include "twi.h"
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}
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#include "Wire.h"
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static inline void TWI_WaitTransferComplete(Twi *_twi) {
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while (!TWI_TransferComplete(_twi))
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;
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}
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static inline void TWI_WaitByteSent(Twi *_twi) {
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while (!TWI_ByteSent(_twi))
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;
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}
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static inline void TWI_WaitByteReceived(Twi *_twi) {
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while (!TWI_ByteReceived(_twi))
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;
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}
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static inline bool TWI_STATUS_SVREAD(uint32_t status) {
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return (status & TWI_SR_SVREAD) == TWI_SR_SVREAD;
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}
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DueWire::DueWire(Twi *_twi) :
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twi(_twi), rxBufferIndex(0), rxBufferLength(0), txAddress(0),
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txBufferLength(0), srvBufferIndex(0), srvBufferLength(0), status(
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UNINITIALIZED) {
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// Empty
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}
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void DueWire::begin(void) {
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// TODO: correct clock values
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TWI_ConfigureMaster(twi, 200000, 200000);
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status = MASTER_IDLE;
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}
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void DueWire::begin(uint8_t address) {
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TWI_ConfigureSlave(twi, address);
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status = SLAVE_IDLE;
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TWI_EnableIt(twi, TWI_IER_RXRDY | TWI_IER_TXRDY | TWI_IER_TXCOMP);
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}
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void DueWire::begin(int address) {
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begin((uint8_t) address);
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}
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uint8_t DueWire::requestFrom(uint8_t address, uint8_t quantity) {
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if (quantity > BUFFER_LENGTH)
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quantity = BUFFER_LENGTH;
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// perform blocking read into buffer
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int readed = 0;
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TWI_StartRead(twi, address, 0, 0);
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do {
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// Stop condition must be set during the receprion of last byte
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if (readed + 1 == quantity)
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TWI_SendSTOPCondition( twi);
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TWI_WaitByteReceived( twi);
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rxBuffer[readed++] = TWI_ReadByte(twi);
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} while (readed < quantity);
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TWI_WaitTransferComplete( twi);
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// set rx buffer iterator vars
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rxBufferIndex = 0;
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rxBufferLength = readed;
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return readed;
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}
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uint8_t DueWire::requestFrom(int address, int quantity) {
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return requestFrom((uint8_t) address, (uint8_t) quantity);
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}
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void DueWire::beginTransmission(uint8_t address) {
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status = MASTER_SEND;
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// save address of target and empty buffer
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txAddress = address;
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txBufferLength = 0;
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}
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void DueWire::beginTransmission(int address) {
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beginTransmission((uint8_t) address);
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}
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uint8_t DueWire::endTransmission(void) {
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// transmit buffer (blocking)
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TWI_StartWrite(twi, txAddress, 0, 0, txBuffer[0]);
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TWI_WaitByteSent( twi);
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int sent = 1;
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while (sent < txBufferLength) {
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TWI_WriteByte(twi, txBuffer[sent++]);
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TWI_WaitByteSent(twi);
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}
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TWI_Stop(twi);
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TWI_WaitTransferComplete(twi);
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// empty buffer
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txBufferLength = 0;
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status = MASTER_IDLE;
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return sent;
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}
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void DueWire::write(uint8_t data) {
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if (status == MASTER_SEND) {
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if (txBufferLength >= BUFFER_LENGTH)
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return;
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txBuffer[txBufferLength++] = data;
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} else {
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if (srvBufferLength >= BUFFER_LENGTH)
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return;
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srvBuffer[srvBufferIndex++] = data;
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}
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}
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void DueWire::write(const uint8_t *data, size_t quantity) {
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if (status == MASTER_SEND) {
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for (size_t i = 0; i < quantity; ++i) {
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if (txBufferLength >= BUFFER_LENGTH)
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return;
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txBuffer[txBufferLength++] = data[i];
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}
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} else {
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for (size_t i = 0; i < quantity; ++i) {
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if (srvBufferLength >= BUFFER_LENGTH)
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return;
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srvBuffer[srvBufferLength++] = data[i];
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}
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}
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}
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void DueWire::write(const char *data) {
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write((uint8_t*) data, strlen(data));
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}
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int DueWire::available(void) {
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return rxBufferLength - rxBufferIndex;
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}
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int DueWire::read(void) {
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if (rxBufferIndex < rxBufferLength)
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return rxBuffer[rxBufferIndex++];
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return -1;
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}
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int DueWire::peek(void) {
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if (rxBufferIndex < rxBufferLength)
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return rxBuffer[rxBufferIndex];
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return -1;
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}
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void DueWire::flush(void) {
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// XXX: to be implemented.
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}
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void DueWire::onReceive(void(*function)(int)) {
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onReceiveCallback = function;
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}
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void DueWire::onRequest(void(*function)(void)) {
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onRequestCallback = function;
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}
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void DueWire::onService(void) {
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// Retrieve interrupt status
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uint32_t sr = TWI_GetMaskedStatus(twi);
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// Detect if we should go into RECV or SEND status
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if (status == SLAVE_IDLE) {
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srvBufferLength = 0;
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if (TWI_STATUS_SVREAD(sr)) {
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status = SLAVE_RECV;
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} else {
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srvBufferIndex = 0;
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status = SLAVE_SEND;
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// Alert calling program to generate a response ASAP
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if (onRequestCallback != NULL)
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onRequestCallback();
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else
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// default response
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write((uint8_t) 0);
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}
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}
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// Receive packet
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if (status == SLAVE_RECV) {
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if (TWI_STATUS_RXRDY(sr)) {
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if (srvBufferLength < BUFFER_LENGTH)
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srvBuffer[srvBufferLength++] = TWI_ReadByte(twi);
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}
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if (TWI_STATUS_TXCOMP(sr)) {
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// Receive completed
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status = SLAVE_IDLE;
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// Alert calling program
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if (onReceiveCallback != NULL) {
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// Copy data into rxBuffer
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// (allows to receive another packet while
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// the main application reads actual data)
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for (uint8_t i = 0; i < srvBufferLength; ++i)
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rxBuffer[i] = srvBuffer[i];
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rxBufferIndex = 0;
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rxBufferLength = srvBufferLength;
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onReceiveCallback( rxBufferLength);
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}
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}
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}
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// Send packet
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if (status == SLAVE_SEND) {
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if (TWI_STATUS_TXRDY(sr)) {
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uint8_t c = 0;
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if (srvBufferIndex < srvBufferLength)
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c = srvBuffer[srvBufferIndex++];
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TWI_WriteByte(twi, c);
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}
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if (TWI_STATUS_TXCOMP(sr)) {
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// Transmission complete
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status = SLAVE_IDLE;
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}
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}
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}
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DueWire Wire = DueWire(TWI0);
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DueWire Wire2 = DueWire(TWI1);
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void TWI0_IrqHandler(void) {
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Wire.onService();
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}
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void TWI1_IrqHandler(void) {
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Wire2.onService();
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}
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